The present invention generally relates to a hoist assembly and more particularly, to a hoist assembly including a movable member which selectively and automatically shifts the center of gravity of the hoist assembly, thereby allowing the hoist assembly to remain in a substantially level position when it is loaded and unloaded.
Hoist assemblies are generally used to lift, elevate, and/or move relatively heavy and/or cumbersome components, devices, and/or other objects. Hoist assemblies typically include several members which are interconnected to cooperatively form a frame or support fixture, and one or more chains, cables, or other connecting members which are selectively attached to the support fixture and to the device or object that is desired to be lifted. The support fixture is coupled to a motor, winch, or other lifting assembly or apparatus which selectively lifts or elevates the fixture and the object or device which is attached to the fixture. These types of fixtures are typically designed to allow the lifted object or device to remain substantially level (e.g., horizontal) while it is being lifted and/or moved, thereby preventing movable components or movable portions of the object or device from being undesirably moved or displaced while the object is being lifted.
One of the major drawbacks associated with these prior hoist assemblies is that the process of loading and/or unloading devices and other objects to/from these prior hoist assemblies is undesirably time-consuming, difficult, and cannot typically be performed by a single person or operator. For example and without limitation, when used to lift an object which has an xe2x80x9coff-centeredxe2x80x9d center of gravity (e.g., a center of gravity which is located remote from the center of symmetry of the object), the support fixture which is used is typically manufactured or formed to be disproportionately or unevenly xe2x80x9cweightedxe2x80x9d in order to compensate for the xe2x80x9coff-centeredxe2x80x9d center of gravity of the object, thereby ensuring that the object and fixture remain in a level position when the object or device is lifted. This disproportionate or uneven xe2x80x9cweightingxe2x80x9d causes the fixture to undesirably reside in an xe2x80x9cunleveledxe2x80x9d or sloped position when it is not xe2x80x9cloadedxe2x80x9d (i.e., when the object is not attached to the fixture), and therefore requires the fixture to be xe2x80x9cleveledxe2x80x9d prior to attaching the object or device to the fixture. Hence, in order to secure and/or remove items to/from these prior hoist assemblies, one individual or operator is required to hold the relatively heavy and cumbersome fixture in a substantially horizontal and/or level position, while another individual or operator connects the object or device to the fixture. Moreover, the relatively heavy weight of the fixture often causes the fixture to slip, drop, or pitch while it is being held, thereby potentially damaging the object or device which is being attached to the fixture.
There is therefore a need for a new and improved hoist assembly which overcomes many, if not all, of the previously delineated drawbacks of such prior hoist assemblies.
It is therefore a primary object of the invention to provide a hoist assembly which overcomes at least some, if not all, of the previously delineated disadvantages of prior hoist assemblies.
It is a second object of the invention to provide a hoist assembly which includes a support fixture which remains in a substantially level position when it is loaded and unloaded.
It is a third object of the invention to provide a hoist assembly which is further characterized by its ability to allow a single user or operator to relatively easily secure and/or attach an object to the hoist assembly.
It is a fourth object of the invention to provide a hoist assembly for lifting an object which includes a movable member that selectively and automatically shifts the center of gravity of the hoist assembly when the object is lifted, thereby causing the assembly and the object to remain in a substantially level position.
According to one aspect of the present invention, a hoist assembly for lifting an object is provided. The hoist assembly includes a plurality of interconnecting members which are selectively coupled to the object; and a fixture which is coupled to the interconnecting members and which is selectively suspended at a first location. The fixture has a movable member and a center of gravity, the center of gravity being aligned with the first location when the object is not being lifted, thereby allowing the fixture to be suspended in a substantially level position. The movable member is movable from a first position to a second position in response to the object being lifted, the movement being effective to cause the center of gravity to shift to a second location, the shift being effective to cause the fixture and the object to remain level while the object is being lifted.
According to a second aspect of the present invention, a method for lifting an object is provided. The method includes the steps of: providing a fixture having a movable member and a center or gravity; suspending the fixture from a point on the movable member which is substantially aligned with the center of gravity, thereby causing the fixture to remain in a substantially level position; coupling the object to the fixture; providing an upward force at the point, effective to lift the object and to cause the movable member to move, thereby shifting the center of gravity and causing the object to remain in a level position.
Further objects, features, and advantages of the present invention will become apparent from a consideration of the following description and the subjoined claims, when taken in conjunction with the accompanying drawings.